"It's not like me to hide things, but I'm in quite a bit of fear about this," Carnie, 43, says on her TV Guide Network reality series taped before she had the January surgery. "That's really the reason why I've put this off, not telling Wendy and Chynna. Something has to be done."

Sitting in between her Wilson Phillips Still Holding On costars and former band mates at lunch, Carnie says, "I want to tell you guys something. I am going to have another type of weight-loss surgery that is going to help me."

Explaining that 12 years had passed since she had a gastric bypass, she says, "I've put two-thirds of my weight back on. The bottom line is my blood sugar levels are getting high, and the risks are worse [with] me staying at this weight."

Among her biggest concerns: diabetes.

"I don't want to become a diabetic," she says. "In a year, I could become diabetic, and I'm not doing it."

Carnie, who said in January that maintaining her weight was still "a struggle," adds on her show, "The scale hasn't moved in two years for me and the stakes are different right now. The opportunity is here and I'm grabbing it."

The singer is reuniting with Wilson Phillips to promote their new album, Dedicated, which drops April 3. The show Wilson Phillips: Still Holding On premieres April 8.
Wilson Phillips Still Holding On premieres April 8 at 9 p.m. ET.